In the field of pedal driven machines, such as bicycles, tricycles, exercise bicycles or the like, numerous examples of support structures, or saddles, are known, which are adapted to support users on a seat surface.
A saddle generally comprises a rigid structure adapted to support the body weight of the user and allows attachment of the saddle onto a bicycle or similar vehicle by suitable fastening means.
In order to reduce compression at the contact points between the seat surface and the user it is common to use elastic and/or shock absorbing elements, generally made of a polymeric foam or a material having a viscous behavior, interposed between the seat surface and the rigid structure.
During pedaling, the inside thigh areas of the user repeatedly contact the side periphery of the saddle, thereby causing periodic rubbing and consequent local irritations, unless particular arrangements are provided.
A possible solution consists in reducing the extension of the rigid structure or making it partly pliable at the side edges of the saddle, said edges being mainly formed by a soft material, adapted to be elastically deformed during the pedaling activity. This allows to reduce the contact action of the side edges of the saddle on the relevant body areas but leads to other drawbacks.
A first drawback consists in that the presence of such pliable edges reduces the surface in contact with the user's body and, as a result, increases the pressure exerted by the saddle.
A second drawback associated with such pliable side edges is that they cause the rigid structure to be permanently, and often unacceptably weakened.
One solution to reduce or avoid contacts and repeated rubbing against the inside thighs consists in using additional soft pads, placed at the side edges of the saddle.
U.S.-A-20020069464 discloses an additional pad to be fitted to the outside surface of a saddle. Such additional pad consists of two substantially parallel soft tubular members, which are connected by a flexible member made of fabric or similar material. The flexible fabric member has such a size that, once it is laid over the seat surface of the saddle, the two soft tubular members are situated along the side edges of the saddle, in areas at highest contact with the inside thighs of the user.
An apparent limit of this solution lies in that the additional pad, when not properly secured, may be displaced during use, due to the motion of legs, and is in any case a supplement member, which has to be repeatedly checked for proper positioning. Further, the use of an additional member necessarily implies a more complex construction, requires particular care in mounting operations, and greatly changes the aspect of the saddle.
WO-A-0051877, U.S. Pat. No. 6,019,422, GB-A-2184698 disclose several embodiments that may be all associated to the same operation principle. The saddle is of the conventional type, with a rigid structure covered with a soft material, which is designed to improve the comfort of the seat surface. Any possible rubbing against the inside thighs of the user is attenuated by appropriate swingable means for securing the saddle to the frame of the pedal operated machine. Such swingable fastening means allow the saddle to rotate through a limited angle about an axis parallel to the longitudinal axis of the saddle. By this arrangement, during the pedaling action, the saddle may rock on the side of the pushing leg and the pressures exerted on the inside thigh are reduced.
A common drawback of all these embodiments consists in the remarkable complicated structure introduced by the use of these swingable fastening means, and by the consequent increase of construction costs.
WO-A-02/12055 discloses a support structure having all the features mentioned in the preamble of claim 1. However, in this prior art the outer peripheral edge of the frame is substantially continuous and has a relatively rigid rim which reduces the flexibility of the frame itself. Thus, the support structure disclosed in this prior art cannot reduce the compression in the vicinity of the outer edge of the frame so as to render less comfortable the pedalling motion.